Question 702543
{{{ 8 }}} m2/hr = rate of painting with roller
{{{ 20 }}} m2/hr = rate of painting with spray gun
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Cost painting {{{ 40 }}} m2 with roller:
{{{ C = ( 40/8  + 1/2 )*11 }}}
{{{ C = 5.5*11 }}}
{{{ C = 60.5 }}}
Cost painting {{{ 40 }}} m2 wwith spray gun:
{{{ C = ( 40 / 20 + 1 )*11 }}}
{{{ C = 3*11 }}}
{{{ C = 33 }}}
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{{{ 60.5 - 33 = 27.5 }}}
Using the spay gun costs $27.50 less than using roller